110 :^n?. g. BEis^THA:\r ok myktacej^. 



n 



receptacle or torus^ or the concrete base of the coroUa and an- 

 droeciam ; its appearance is more frequently that of the former than 

 of the latter, but its consistence is generally different from both. 

 It does not exist in all plants, and, as far as we know, has no 

 definite function to perform in the floral economy. It can scarcely 

 therefore be called a distinct organ ; and we describe it rather as 

 a part of the flower generally, leaving it an open question as to 

 whether it belongs to the axis or to the appendages. "When it 

 exists it extends from the calyx to the gynsecium, is often more 

 or less adnate to the one or to the other, or to both, sometimes lining 

 the calyx-tube by a thin layer more or less thickened at the margin, 

 and there bearing the petals and stamens, sometimes closely adnate 

 to and covering the ovary with a thin layer thickened at the top, 

 round the style, into the so-called epigynous disk of Eubiaceae 

 and allied Orders, and then blended often with the thickened sum- 

 mit of the ovary or base of the style. Sometimes it expands into 

 glands or filament-like appendages, or into an annular cup between 

 the stamens and the style, or more rarely between the petals and 

 stamens, still more rarely outside the petals. These appendages 

 are sometimes definite in number, and even symmetrical wdth other 

 parts of tlie flower, but they do not, as far as I am aware, assume 

 the appearance of a real whorl of floral leaves ; and all descriptions 

 of the disk, whether it be called staminal,hypogynous,perigynous, 

 or epigynous, must be considered to be descriptions of apparent 

 forms, independent of all theories. 



It must be observed also that, notwithstanding the adoption of 

 the theoi'y of concretion of organs, it is much the practice, for con- 

 venience' sake, to describe one organ as inserted upon the other, 

 to which there is perhaps no objection if it be perfectly understood 

 that the description is of apparent, not theoretical insertion. And 

 it is usual to describe the least prominent organ of the two as in- 

 serted on the most prominent, or, in the case of floral whorls, those 

 of the least concrete whorl as inserted on the more concrete : thus 

 in Chailletiacese, the inflorescence is usually described as inserted 

 on the petiole ; in Tilia^ on the contrary, the bract is said to be in- 

 serted on or attached to tlie pedicel. In most Myrtaceie the caly^- 

 tube or its lower portion is described as adnate to the ovary, the 

 disk, on the contrary, as adnate to or lining the upper part of the 

 calyx-tube. In Calycantheae again, and in some Nymphaeacese, ^^"> 

 the sepals are adnate to or inserted on what may be called either an 

 enlarged receptacle or the petaline and staminal disk, whilst in Ly- 

 thrarieae and others the petals and stamens are adnate to, or lo- 



